1. Field of the Invention
The present invention relates to a sensing device, and more particularly, to a pressure sensing device.
2. Discussion of Related Art
A tactile sensor refers to a sensor capable of sensing information of surrounding environments such as contact pressure, vibration, surface roughness, temperature change, etc. Such a tactile sensor is not only used for various medical diagnostics and surgeries, a sensation sensor for a prosthetic hand, etc. but expected to be used in technologies for implementing a virtual environment.
In addition, a tactile sensor is directed at imitating tactile sensibilities of humans, where humans are provided with a slow-adapting (SA) type receptor in which an intensity of output is proportional according to an intensity of stimulus such as merkel or ruffini receptors, and a fast-adapting (FA) type receptor which is more sensitive to a change in stimulus than an intensity of stimulus such as missner or pacinian receptors.
Both types of receptors may generate a pulse type electric signal by a stimulus being applied thereto. In the case of the SA type, a repetition rate of consecutive pulses changes according to intensity of a stimulus, and in the case of the FA type, a limited number of pulses are generated at a specific intensity of a stimulus according to a change in stimulus intensity. Humans distinguish various types of tactile sensations through time intervals between such pulses.
Most tactile sensors developed so far have been SA types in which an intensity of output is proportional according to an intensity of stimulus. On the other hand, research into the FA type which can only sense a change in stimulus and output an electrical signal of a pulse type has been lacking.